A rotating electrical machine in the related art has a cooling mechanism configured in such a manner that cooling oil is stored in a housing that houses a rotor and a stator of the rotating electrical machine and fins are provided to one of end plates provided at both ends of the rotor (PTL 1). A height of the cooling oil is adjusted so that fins are soaked in the cooling oil when the fins come to a lowermost end position in association with rotation of the rotor. According to this configuration, when the rotor rotates, not only is wind developed, but also the cooling oil is scooped up by the fins. Hence, the stator is cooled efficiently.